The proposed work involves the application of nuclear magnetic resonance measurements to the study of water and small solutes in protein crystals and tissues. The nmr relaxation time measurement provides a direct and nondestructive means for study of the whole tissue, but the tissue presents an extremely complicated system. The main initial thrust of the work is therefore directed at the study of protein crystals which provide a sensible and critical model system for the more complex tissue. The specific crystal problems to be studied include water relaxation times in a variety of protein crystals; the nature of other solutes in protein crystals such as sodium ion, acetate ion, etc; the kinetics of water exchange with the protein surface in the crystal phase; and the structure of metal binding sites in the crystal phase compared with the structure in solution, and the mobility of protein surface side chains in the crystal.